Photodetector response is a function of temperature. Each photodetector has a temperature at which responsivity is maximized. However, this optimum temperature may not be equivalent to atmospheric temperature. Often, atmospheric temperature is lower than the optimal temperature, especially when a photodetector is used at high altitude or in severe weather conditions. By heating the photodetector, the detector's temperature can be thermally stabilized at or around the optimum temperature, thus maximizing photodetector responsivity under any atmospheric conditions.
The semiconductor substrate in a photodetector is often mounted in a package. To heat the photodetector, heaters have been mounted outside of the enclosure. In order to raise the detector temperature the packaging must also be heated. Much of this heat does not reach the semiconductor substrate. This wastes power and means that significant time elapses while the semiconductor substrate temperature is raised to the optimal temperature. Furthermore, if there are other electronics along the thermally path between the heater and the semiconductor substrate, these electronics may be damaged during heating.
Consumer electronics, such as digital cameras, cell phones, and laptop computers could benefit from photodetectors that consume little power and reach optimal detection efficiencies quickly. Various weapons systems would also benefit from low power consumption and the ability to quickly raise the photodetector temperature to its optimum.